Ophthalmic mounting and method of forming same



March 13, 1934. H E 1,950,747

OPHTHALMIC MOUNTING AND METHOD OF FORMING SAME Filed March 12, 1932 Patented Mar. 13, 1934 UNITED STATES OPHTHALMIC MOUNTING AND METHOD OF FORMING SAME My invention relates particularly to connections between glass and metal parts such as is required in the mounting of an optical lens between the metal straps of a nose piece or car piece.

Usually such a lens mount includes a screw extending through the strap and the lens and tightened to clamp the strap arms against the glass. Because of the hard nature of glass it is difficult to obtain a secure grip by the metal straps on opposite faces of the lens as the straps can not bite into the glass. Furthermore, the lenses frequently have contours which are not flat or parallel and such contours tend to effect an engagement with the strap along restricted areas or lines instead of over the entire surface of the strap opposing the lens. The opening in the glass for the screw must necessarily be drilled substantially larger than the diameter of the screw and this is likely to result in lost motion between the screw and the lens.

The object of the present invention is to provide a suitable mounting element which may be clamped between the strap and the face of the lens so as to produce supporting engagement between the strap and the lens throughout a substantial area of the strap opposing the lens. Preferably such engagement shall be of yielding nature initially to permit the washer to adapt itself to variations in surfaces and pressures. Also 4) it is desired that the washer may be expanded by the clamping operation and by absorption of moisture so as to equalize the pressure at all points. While the lens must be held securely by the straps, it is also desirable to provide for some 5 relative movement between them throughout their useful life on account of the different coeificients of expansion of glass and metal which tends to cause fracture of the lens if the strap grip thereon is too rigid.

It is a further object of my invention to provide a washer which in part may be forced into the lens opening to seat the screw transversely thereof and eliminate the lost motion tendency.

Washers used as described in eye-glasses must necessarily be of very small size and it is a further object of my invention to provide these washers in a form which will be convenient to handle and apply to the lens during the assembly thereof with the strap.

In the accompanying drawing which illustrates a selected embodiment of my invention- Figure l is an elevation of a pair of eye-glasses showing the method of applying the washers thereto.

Figure 2 is a detail view of the washer strip.

Figure 3 is an individual washer which has been severed from the strip.

Figure 4 is a section through the glass and a holding strap with a washer in place.

Figure 5 is a similar section showing the application of a screw holding element and the distortion of the washer thereby.

Figure 6 is a similar section illustrating a tapered form of lens as mounted in the ear piece strap of a pair of spectacles.

The lens 1 and nose piece 2 with strap arms 3 and 4 and the holding screw 5 are of the usual construction. My novel ophthalmic mounting device consists of an elongated, narrow thin strip 6 of sheepskin, parchment or other form of rawhide which has been tightly compressed to collapse the cells thereof. The strip has a series of perforations 7 and lateral indentations 8 to provide a series of washer elements 9 interconnected by attenuated portions 10 which may be readily severed by cutting, twisting or tearing apart. V

The end, or any other portion, of the strip 6 is inserted between at least one strap arm and the face of the lens, as indicated in Figure 1, so as to align one of the perforations '7 with the openings in the lens and strap. The screw 5 is then inserted through the strap, lens and washer and the washer secured thereby is severed from the remainder of-the strip. 'The tightening of screw 5 not only draws the lens tightly against the adjacent face of the washer but also forces the central portion of the washer into the opening 11 in the lens to form a short bushing-like projection 12 (Figure 5) which surrounds the screw and fills the space between the same and the sides of the opening 11.

After the parts are clamped together as indicated they preferably are dipped in water which is absorbed by the rawhide causing the cells to expand and be distorted so as to increase the pressure on the glass and at the same time distribute it equally over the surface engaged by the washer and strap arms. Upon subsequent exposure to the air, the moisture will evaporate and the washer will harden sufficiently to maintain the tight engagement between the lens and the strap arms.

The feature of absorbing water to expand after initial pressure has been applied by the screw is particularly advantageous where a lens having non-parallel faces is to be mounted, such as lens indicated at 13 in Figure 6, and it will be noted that the washer 14 will function as described above irrespective of the contour and the inclination of the opposite faces of the lens and irrespective of whether or not the strap arms 15 and 16 are disposed at the same angle as the faces of the lens.

The washer completely fills the space and forms an adequate support between the lens and strap to tightly hold the lens. Yet it is elastic and is capable of receiving and absorbing strains from tight screwing up of the mount or from unequal expansion and contraction of the glass of the lens and of the metal straps during use which condition probably causes a large majority of the fractures of lens mounts.

I illustrate the washer as being applied between the lens and one arm of the strap and ordinarily this will be adequate, but it will be understood that washers may be applied to both faces of the lens if desired and also that one or two washers may be used in combination with the lens mounting element described in Patent No. 1,430,114 issued to me, September 25, 1922.

Other materials than rawhide may be used but obviously for the most complete satisfaction, the material should possess the characteristics of rawhide to the extent that it is compressible, yielding hygroscopic, and capable of hardening to a substantial degree upon exposure to the atmosphere after being moistened.

The invention is not limited to the mounting of eye-glass lens but may be embodied in other similar mountings where it is desired to grip glass between metal members and particularly where the holding elements are of small dimensions. Irrespective of variations in details of construction, I contemplate the exclusive use of any modification of my invention coming within the scope of my claims.

What is claimed is:

1. A lens mounting including a strap of U- shape to fit over the edge of the lens and to extend inwardly therefrom a substantial distance, a flat round washer of hygroscopic compressed cellular material which expands when moistened and hardens when exposed to the air, and is of restricted diameter to underlie the end portion only of the strap and a holding element extending through the lens, strap and washer and compressing said washer between the lens and the strap.

2. The method of mounting an ophthalmic lens which is characterized by inserting a flat Washer of hygroscopic compressed cellular material, which expands when moistened, between the lens and its strap, inserting a securing element through the lens, washer and strap, the diameter of the element being substantially less than the diameter of the opening therefor in the lens, and then tightening said securing element to distort said washer between said lens and strap and to force a portion of the washer into the element opening in the lens to form a bushing surrounding the element and tightly fitting the opening in the lens and then moistening the washer and bushing forming material.

3. The method of forming a lens mount which consists in inserting a flat washer of rawhide between the lens and the strap, inserting a holding elementthrough the lens, washer and strap, and tightening said element to clamp the washer between the lens and the strap and then moistening the washer.

4. The method of mounting an eye-glass lens in a metal strap which is characterized by the insertion of a perforated elongated strip of hygroscopic compressed cellular material, which expands when moistened, between the lens and its strap, inserting a holding element through the lens, strap and a perforation in said strip, tightening the element to clamp the inserted portion of the strip and then severing the clamped portion of the strip fromthe remainder thereof.

5. The method of forming a lens mount which consists in inserting a flat washer of hygroscopic compressed cellular material, which expands when moistened, between the lens and the strap, inserting a holding element through the lens, washer and strap, and tightening said element to clamp the washer between the lens and the strap, and then moistening the washer.

6. The method of mounting an eye-glass lens in a metal strap which is characterized by the insertion of a perforated elongated strip of hygroscopic compressed cellular material, which expands when moistened, between the lens and its strap, inserting a holding element through the lens, strap and a perforation in said strip, and then severing the clamped portion of the strip from the remainder thereof.

H. C. REES. 

